Producing amplified current variations.



E. WEINTRAUB 61: M. O. A. LATOUR.

PRODUCING AMPLIFIED CURRENT VARIATIONS.

I APPLICATION FILED NOV. 26, 1907. 921,93Q0 Patented May 18, 1909.

Fig. 2.

Inventors: Tflarius CJI. Latour,

Witnesses: 1%. KZZ/W Ewtraub,

. fitt'y.

EZECHIEL WEINTRAUB, or soHEnEoTAoY, NEW YORK, AND MARIUSHC. A. LATOURZZOF PARIS,

FRANCE, ASSIGNORS TO GENERAL ELECTRIC COMPANY, CORPORATION OF NEW" YORK.

Specification of Letters Patent.

PRODUCING AMPLIFIED cuignnn'r VARIATIONS.

To all whom it may concern:

siding at Schenectady, county of Schenec tady, State of New York,-and MARrUsC. A. La'ror'n, a citizen of France," residing atlaris, France; have invented certain new and useful Improvements in Producing Amplified CurrentVariations, of which the p stood by reference -to the following descrip- -tion"taken in connection with the accompanying drawings, inwhichfollowing is a specification.

It is desirable in many instances, as for" example, in the arts of telegraphy, telephnecessary to maintain an arc.

ony and wireless telegraphy to be able to:

produce large'currentvar ations in response to. small current disturbances or pulsations.

The weak current impulses at the receiving 3 station of a w1reless telegraph system or at the receiving end of a telegraph line, by.

being thus magnified or reproduced in gieater magnitude, may thus .be rendered much more easlly and readily detected. I, Our present-invention relates to a device suitable for accomplishing such purposes, though we wishit to be understood that its field of usefulness is not to be limited to the particular embodiment described.

I 11 carrying our invention into practice we" make use of the fact, observed by us, that the resistance, if we mayso use the term, of a mercury 'vapor device or lamp, instead of being approximately inversely proportional to the current when such a lamp is operated normally with a mercury arc, is of widely different character when the-current discharge or flow in the lamp is less than that In such a case the voltage across the tube instead of being constant with variations of current de creases rapidly with increase of current. The. resistance of the tube may thus be said to be negative. This property We utilize by connecting the tube in circuit in such a way that the voltage impressed thereon .is varied in response to the signal 'curreuts orother currents which may be utilized to secure the desired amplified current. varia-' will-be an. extraordinary decreasein the resistance of the tube and a correspondlng 1ncrease in the current. To secure the benefits of our invention We will poi nt out that The features of novelty which'character- .ralityof electrodes.

produce and maintain an arc discharge, since it is onlydhrough this low current range of the volt-ampere characteristic that the voltage across theterminals of the tube decreases with increase of current.

ze our invention arepointed out with par ticularity in the appended claims. Theinventio'n itself, however, will be better underi-Figu1ie represents diagrannnatically one embodiment of our invention, while Fig. 2 is anexplanatory diagram.

In Fig. l the source of current variations or'si-gnal currents is represented conventionallyl bya microphone or transmitter l of any suitable form associated with a local circuit containing a source ofcurrent such as the m E-n STATES PATENT onricni r te td a is, 1909. Application filed November 26, 1907. Serial N 0. 403,867. v

battery2. It will be understood that such a'- .'-"source offcurrent variation is intended merely as illustrative and that to any other source our invention may be applied according to circumstances. The transmitter 1 and battery'i are arranged in local circuit in cluding the primary 3 of a transformer and a'vapor electric device at. The primary 3 receives the current pulsations and transmits them inductively by means of the secondary winding -t to any desired point distant or otherwise, where they may be received by a telephone receiver 5 or by any other suit able receiving device;

The vapor electric device 4 consists of an evacuated glassvesselor container of any;

suitable form "and is provided with a plu The electrode 6 of mercury is the main negative electrode or cathode and is provided with a small platinum wire 7 projecting from its surface to render the cathode spot of the arc discharge stationary. The are discharge referred to is maintained constantly between this cat-h-. ode 6 and the anode 8 of artificial graphite or other suitable material. An auxiliary electrode. 9 of mercury arranged adjacent to the cathode Gserves in a well-known way to permit the arc tobe started between the electrodes (Land 8. ,The source of current for this are may be of anysuitable character as for example, a-"battery 10. This battery is connected at one end to the cathode 6,

while its other terminal is connected through the current-limiting resistance 11 to the electrodes 8 When the arcibetween the auxiliary electrode 9 and-electrode. 6 isproduced by shaking the apparatus to prodnce momentarycontact, another are is immediately fornied be tween the cathode 6 and the anode 8. The starting are; being no longer necessary the auxiliary 9 may be cut out of circuit either by the presence of a resistance 12 or by a switch 13.-

When the are between the anode 8 and the cathode 6 is in existence the space he tween the'cathode 6 and any other electrode,

such as 14, is rendered conductive for current from any suitable source.' In the ar-' .rangement shown, the source ofcuri'ent 2 1n the space between these electrodes. The re.-

sistance of this local circuit is adjusted, as for example, by a resistance 15, so as to keep the current at a value lower than that which would produce an are between the electrodes 6 and' 1 1 inthe vapordevice 4.- he current which then" liows is of the nature of a leakage current and obviously of relatively small value. The volt-ampere characteristic of the vapor device or tube-- covering the range in'which the current flow in the tube is'never sufficient to produce anarc, is represented at 16 in Fig. 2 of thedrawing i n which ordinates of the curve indicate voltages across the tube, whilej abscissac represent currents. In both cases the voltages and currents are reckoned fro n' the origin 0. It will be noted that Wlillllil.

that range on the curve 16 between the points 17 and 18, the voltage on the-tube decreases rapidly with increase of curient. The local-"c rcuit in Fig. 1 being adjusted to come within the range of currents between 17 and 18, it will now be evident that aslight decrease of resistance, due to the action of the transmitter 1, will have the effect, in the first instance, of causingan increase of current in the local circuit. Co-

inoidently therewith the voltage across the terirriguals of the electrodes 6 and 14 will drop r'as seen by the curve in Fig. 2, and the I current will still further increase until the increased drop in resistance in the circuit external to the vapor device cuts down the voltage impressed on the tube, to a point where a balance is reached. It will thus be evident that a much larger relative variation of current will be produced by.. the action of the transmitter 1 than would bev the case if the resistance, so-called, of the device were not negative.

here we have spoken of" the resistance of the vapor device as being negative, we

desire to distinguish from a condition which would be present if an arc were actually to be allowed to form in the device. If this were the case the tube would then be working on the flat or rising portion '19 of the volt-ampere characteristics iii which case, within working limits, the voltage across the tube would be practicallyconstant irrespective of current variations. By working on that portion of the volt-ampere characteristic at which the tube voltage decreases with increase of current, We obtain a very great amplification of current variations. \Ve are enabled to work on this portion of the volt-ampere characteristic by maintaining continuously an auxiliary are from the cathode 6 and thereby secure the advantageous results before mentioned.

\Vhat we claim as new and desire to secure by Letters'latent of the-United States, I w

-1. The combination of' a vapor electric device, means for causing current to flow -;--t-l1ei'8ll1 of a value less than would be suf- 86 ficient to maintain an" arc, and means'for =instituting current disturbances inthe circu-it ofsaidvapor device, which current dis-. --turbances are greatly magnified by the mega- .veresistance characteristic of the device. I 90 he combination of. a vapor electric dev c'ge, means for initially opera-ting said 'E'devic'e at a current density less "than that'- ,"necles'saryto produce an-ar'c, and means'ex tern'lil to said device for varying the resistan'c'e iii' the circuitthereof.

3. The combination of avapor electric device, means for rendering the same conductive for current, means for passing cur rent t-herethrough of a value insufi'icient to .100

maintain an.arc, and means for instituting current variations in said circuit.

4. The combination of a vapor electric device, means for rendering the same conductive for current, means for passing current therethrough of a value 'insufiicient to- -inaintain an arc, means for instituting cur- I rent variations in said circuit, and means for noting said current variations.

5. The combination of a vapor electric device, means for maintaining said device in a conductive condition, means for passing current therethrough of a value insuflicient to maintainan arc, and means for instituting current variations in said circuit.

in witness whereof, VEINTRAUB has hereunto set his hand this 11th day of October, 1907, and LAToUn has hereunto set his hand this 9th day of November, 1907 EZECHIEL WEINTRAUB. MARIUS A. LATOUR.

lVitnes'ses to VVeintraub:

ORI-ORD, FRANICQI, Donn. Witnesses to Latour: DEAN B. Mason,

ALE-TA DAmza MARSHALL. 

